Boat hull



J. E. LANGSTAFF 2,139,831

BOAT HULL Filed Jan. 50, 1936 ATTORNEYS Patented Dec. 13, 1938 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to boat hulls, and more particularly to hulls so shaped that the initial displacement of the water and its passage rearwardly will create a minimum amount of agitation upon the side walls of the hull and also minimize the skin friction therebetween.

One object of the invention is to provide a hull having a bottom and a centrally disposed well depending therefrom for receiving the motive power, between which bottom and rear of the well a partial vacuum will be obtained, when in motion, to create a suction for drawing the exhaust gases from the engine, thereby minimizing the sound of the explosions of the gases from the engine and reducing the friction of the water on the bottom.

Another object is to provide a hull with hollow triangular-shaped rudders so disposed as to direct the current of water, caused by the forward movement of the hull toward the propeller and reducing the pressure of water on one or the other side of the propeller, as required, when changing the direction of the forward course of the hull.

Another object is to provide certain improvements in the form, construction and arrangement of the parts whereby the above named and other objects may effectively be attained.

A practical embodiment of my invention is represented in the accompanying drawing, in which Fig. 1 represents a side elevation of my improved hull having a portion of the cabin thereon and portions broken away to show parts within;

Fig. 2 represents an inverted plan view of the same;

Fig. 3 represents a rear elevation of the same, a portion of which is broken away to show a portion of the rudder mounting; and

Fig. 4 represents a vertical section taken in the plane of the line IV-IV of Fig. 1, looking in the direction of the arrows.

The hull comprises a main bottom denoted by I, upwardly diverging side walls by 2, a vertical front wall by 3, and a vertical rear wall by 4, which front and rear walls are connected with the bottom and side walls. A bow 5 having upwardly and outwardly curved side walls 6 is connected to the front wall 3, and a deck I is joined to the front wall 3 and upper edges of the side walls 6 of the bow to form a closed compartment for the storage of motor fluid, such as gasoline or other fluid. This compartment instead of being used for the storage of motor fluid may contain fluid to serve as ballast. The main bottom I extends throughout the length of the side walls and is provided with a well depending therefrom, in which the motive power, in the present instance, a gasoline driven engine 8, for the vessel is located. This well is provided with vertical side 5 walls 9, a vertical front wall II], a vertical rear wall II, and a bottom I2, which bottom extends rearwardly of the rear wall II to form a skeg I3. This rearwardly extended bottom I2 of the well is also extended forwardly of the side walls 9 and front wall I0, and is inclined upwardly at M to join the main bottom I at the front wall 3. The side walls 9 of the well are extended forwardly of the front wall In and are triangularly shaped at I5 to fit and be joined to the main bottom I and the inclined bottom I4, so as to form a closed compartment for the storage of motive fluid supply, ballast, or may be used for buoyancy purposes.

The vessel is propelled by any well known or approved means, in the present instance, I have shown a propeller I6 mounted on a shaft l I journaled in the rear end wall II of the well and in a strut I8 secured between the main bottom I and the skeg I3. Thus, it will be seen that the propeller I 6 is enabled to work to its full efiiciency in the volume of solid water between the main bottom I and the skeg I3, and, as a result of this construction, a partial vacuum will be set up in the angle at the junction of the rear wall I I of the well and the main bottom I.

I also find it advantageous to locate an exhaust outlet pipe I9 in the main bottom I adjacent the wall II of the well, which outlet pipe I9 is connected with the exhaust pipe 20 of the engine through a three-way pipe fitting 2|, so that the exhaust gases and oil discharged therethrough will serve not only to muflie the sound of the explosions of the gases but also reduce the skin friction of the bottom on the water. Furthermore, by exhausting the gases at this point a suction will be created, thereby drawing the exhaust gases away from the engine and assisting to increase the speed of propulsion in the forward movement of the hull. In order to compensate 5 for certain conditions, the exhaust gases from the engine may be passed from the exhaust pipe 20 to the three-way pipe fitting 2|, thence through a mufiier pipe 22 to atmosphere, as shown in Fig. 1. It will be understood that, when the vessel is in motion, this mufiier pipe 22 may be closed by any well known or approved means.

The means of steering the hull comprises a pair of rudders 23, 24 located on oposite sides of the propeller I6 in position to be oscillated between the skeg l3 and the main bottom I. Each rudder is constructed with three vertical walls joined together at their vertical edges, the upper and lower horizontal edges of which walls are connected to triangular plates, so as to form a hollow compartment which may function to receive ballast or provide buoyancy, as desired. Each rudder is provided with a steering post 25, the lower end of which is stepped in the end of a transversely arranged plate 26 secured to the skeg I3 in position to extend laterally therefrom. Each steering post extends upwardly through a pipe 21 fixed'on the main bottom I and may be journaled therein in any well known or approved manner. The upper end of each steering post 25 is arranged to be journaled in a main deck 28 and provided with a quadrant 29. The quadrant on each post may be connected so that the rudders may be actuated simultaneously or each rudder may be operated separately in the usual manner. A motive fluid supply tank is mounted on the vertical wall 4 of the hull and may be connected with the supply tank in the bow 5, as well as to the engine 8 in the usual manner, if desired.

In Fig. 2 I have shown the rudders 23, 24 positioned to steer the vessel in a straight line, and the propeller l6 rotating in-the unimpeded full body of water. When the rudders are turned to the position shown in dot and dash outline in Fig. 2 the course of the vessel will be to starboard, in which instance, the rudder 23 will be turned inwardly toward the propeller l6 so that the pressure of the water against the propeller will be lessened and the wide vertical wall of the rudder so disposed as to increase the resistance of the water, as well as shield the propeller IE on that side. The rudder 24 in this instance is actuated with the rudder 23 so that it will be turned outwardly away from the propeller, thereby allowing a maximum body of water to flow to that side of the propeller, while one of the smaller vertical walls of the rudder resists the pressure of the water and does not shield the propeller against the flowing pressure. It will, of course, be understood that the rudders will be turned in the opposite positions from that shown in the dot and dash outline in Fig. 2 if it is desired to steer the vessel to port, in which position the action of the rudders on the water with respect to the propeller will be reversed from that above described.

It is understood that various changes may be resorted to in the form, construction and arrangement of the several parts without departing from the spirit and scope of my invention, and hence I do not intend to be limited to the details herein shown and described except as they may be included in the claims.

What I claim is: I

1. In a boat hull having a Hat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a skeg, and a hollow rudder mounted .to be swung between the fiat bottom and skeg, said rudder being triangular in cross section and having straight rectangular vertical walls of unequal areas and flat top and bottom walls.

2. In a boat hull having a flat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a skeg, and hollow rudders mounted to be swung between the flat bottom and skeg on opposite sides thereof, each of said rudders being triangular in cross section and having straight rectangular vertical Walls of unequal areas and flat top and bottom walls.

3. In a boat hull having a flat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a skeg, and a hollow rudder mounted to be swung between the flat bottom and skeg, said rudder being triangular in cross section and having straight rectangular vertical walls of unequal areas and flat top and bottom walls, the straight vertical wall of the least area being disposed toward the rear of the hull.

4. In a boat hull having at fiat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a skeg, and hollow rudders mounted to be swung between the fiat bottom and skeg on opposite sides thereof, each of said rudders being triangular in cross section and having straight rectangular vertical walls of unequal areas and fiat top and bottom walls, the straight vertical wall of the least area being disposed toward the rear of the hull.

5. In a boat hull having a flat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a skeg, and hollow rudders mounted to be swung between the flat bottom and skeg on opposite sides thereof, each of said rudders being triangular in cross section and having straight rectangular vertical Walls of unequal areas and fiat top and bottom walls, the straightvertical wall of the least area being disposed toward the rear of the hull and the outer vertical wall of each rudder being arranged substantially at right angles to said rear wall of least area.

6. In a boat hull having a flat bottom, a rectangular shaped well centrally and longitudinally disposed to depend from said bottom, the bottom of said well extending to the rear of the hull to form a wide skeg and an open chamber adjacent the rear wall of the well, a motor means disposed in the well, and an exhaust pipe for said means having its outlet fixed in the'flat bottom of the hull in position to exhaust downwardly into said chamber, whereby the exhaust gases from said motor means will be discharged into the chamber and pass upwardly and rearwardly along the flat bottom of the hull and relieve the surface friction thereon.

JOHN ELLIOT LANGSTAFF. 

